I guess the first thing to consider is how big of a tank you can purchase given the room you have - or if you have plenty of room, what type of fish you want to keep and then look up required tank sizes for those type of fish.

There are tons of member tank pics. here and a helpful Tropical Fish Profiles section at the top of the main page in the blue menu bar.

Hello and Welcome, glad to have you with us:) Are you considering a betta, or another type of fish? There are some great tanks at Petco, and Petsmart, and a wide variety of silk, and real plants to keep your fishy happy I have mostly 3, and 5 gallon tanks, some with LED changing color lights, for room ambiance, and then I have another one with the moonlight effect, like a glow light, 6 bettas, 4 boys, and 2 girls:)

Hello, and welcome to the forum. :)
Well, as long as you know what it's going to cost you, have enough time, and if you're very willing to give them the best care as possible, go for it. I've spent over $400 for a 3 gallon and a 20. Any pet is expensive in its own limits, even fish.
All I can say for any other advice is to get the biggest tank you can, never miss your scheduled water change, and feed your fish a variety of foods.